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- DOS/NT started in 1988 as an experiment in writing device drivers in C for
- Microsoft's MS-DOS1. Both block and character device drivers were written,
- along with special C data structures to match the MS-DOS request packet. It
- was then recognized that using the same techniques, an operating system
- could be written that would take advantage of the C language features and
- would require much less time to develop than the traditional assembly
- language techniques. Although UNIX2 had proven this earlier, it was not
- tried with a traditional pc operating system.
-
- At this time, a minimal operating system using the device drivers written
- earlier along with a new 8086 interrupt API was developed. It was called
- XDOS and proved to be a functional operating system. This new operating
- system was used to develop booting techniques and a C library SDK was
- developed for it.
-
- XDOS enhancements were started in 1989 and MS-DOS was chosen as the new API.
- A more advanced architecture was also developed. This included the use of
- an IPL (intermediate program loader) to set up the operating environment
- prior to loading the operating system itself and reentrant system calls
- facilitating real-time applications. This version, know as NSS-DOS, was
- completed and demonstrated in 1991. As a result of these demonstrations,
- NSS was approached to supply source license for this operating system by a
- major defense contractor. The only new requirement - it had to run on 68K
- processors.
-
- This presented a new challenge. Due to the MS-DOS model used for the API,
- NSS-DOS relied heavily on a segmented architecture. To meet this challenge,
- a major redesign of NSS-DOS was undertaken. New proprietary techniques were
- developed that allowed the same source to be compiled on a variety of hosts
- and with a wide range of compilers. This new version, DOS/NT, was the result o
- f this new project. The kernel was redesigned as a micro kernel along with
- logical separation of the filesystem, memory and task managers. A new DOS
- API was designed along with a new DOS SDK to guarantee portability.
- Additionally, all processor unique code was separated from the core
- functions. The result is the highly portable operating system that DOS/NT
- represents.
-
- MS-DOS is a trademark of Microsoft Corporation.
- UNIX is a trademark of USL, Inc.
-
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- Networks Software Systems, Inc.
- 23 Cornwall Road
- Freehold, NJ 07728
- Voice: (908) 206-0320
- Fax: (908) 303-9364
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